Electronics Protection - Spring 2015 - (Page 14)
Identifying the Ideal Mechanical PCB Hardware for
Marc Caiola, Platform & Marketing Leader, North America
Mechanical Printed Circuit Board (PCB) hardware and retainers are an important component in any electronic subassembly or
system, as they provide the required clamping force and placement to board module assemblies, electronic subracks or system
chassis'. These essential mechanical components ensure complete
To ensure optimal performance of the electronic system, the
PCB must be supported and placed in correct alignment. If a
board does not have a secure clamp, the board may not only fall
out of alignment, but it may also start to flex, which can result in
system failure or accidental ejection of the board.
In addition to board protection and placement, retainers are
ideal for thermal management with sensitive electronics. Retainers
prevent wear and failure by transferring heat away from electronic components, while delivering higher retention force on the
board. PCB handles, code keys, injectors and ejectors can provide
a failsafe solution for ensuring proper board placement, insertion
With today's diverse electronic systems applications, a variety of
PCB hardware and retainer solutions may be deployed to address
a broad range of unique protection requirements. This article
introduces different types of PCB hardware solutions and their
applications. These range from general electronic systems requiring basic board retention and placement to complex high-tension,
clamping force applications found in high shock and vibration
environments, such as industrial and transportation applications.
Types of Mechanical PCB Hardware
With multiple styles available, correctly specified PCB hardware
can provide a reliable protection solution for diverse applications.
Examples include: injectors and ejectors, nylon and metallic card
guides, PCB tainers, Card-Lok and Wedge-Lok board retainers,
code keys and conduction-cooled assemblies.
Injectors and Ejectors
PCB injectors and ejectors are generally used in both sheet
metal and cold wall applications to facilitate the installation and
removal of standard PCBs with high-density backplane interconnects. Available in metal and plastic design, in addition to various
lever styles and finishes, injectors and ejectors can be installed
and removed in diverse applications. These components are
levers, which are fitted to the PCB and are retained in front of the
selected PCB guide. Injectors and ejectors are designed to ensure
simple insertion and extraction of the PCB from a subrack, case or
Nylon and Metallic Card Guides
Nylon and metallic card guides provide an economical and
quick solution to effectively align and mount PCBs. With easy card
insertion, these card guides firmly support and protect the board.
Card guides are available with tough, electrically insulating nylon
or metallic material.
PCB-Tainers feature a spring-action card retention design and
provide a low-cost board alignment and retention solution for
sheet metal applications. PCB-Tainers are optimal for providing
Spring 2015 * www.ElectronicsProtectionMagazine.com
protection against basic shock, vibration and unique grounding
characteristics, often found in harsher environments.
Card-Loks and Wedge-Loks
Card-Lok and Wedge-Lok
retainers are designed to
secure PCBs to the cold wall
in cold plate-heat exchanger
Card-Lok and Wedge-Lok retainers
applications. They are typiare designed to secure PCBs to the
cally mounted to the board
cold wall in cold plate-heat exchangor subrack. Providing retener applications.
tion to the card guide, the
Card-Lok retainer clamps to
the board edge to ensure secure clamping at the connector side,
top and bottom edges and backplane side.
Advanced Card-Lok and Wedge-Lok retainers employ a screwactuated wedge action that locks the PCB in place with the use of
a standard hex wrench, establishing the secure hold required for
military two-level maintenance systems. Eliminating the need for
a torque wrench, this design applies no insertion and extraction
force on the PCB, removing the risk of over tightening to prevent
damage to the board and Card-Lok during installation. Card-Lok
retainers are available in various lengths, individual wedge dimensions, mounting configurations and finishes to satisfy diverse application requirements.
Conduction Cooled Assemblies and Code Keys
assemblies (CCAs) are
generally used when passive free air convection or Metal card guides provide an economical
active forced air cooling
and quick solution to effectively align
is not possible, such as
and mount PCBs.
in space applications, or
where creating airflow
with moving parts might affect the reliability of the system. Featuring a robust, lightweight aluminum design, CCAs deliver high
thermal conductivity, while ensuring sufficient structural support.
CCAs consist of a conduction-cooled frame, backing plate, extractors and wedge clamps. They are designed for PCBs requiring
cooling in severe environments where convection cooling is not
practical. CCAs are available in numerous configuration sizes and
finishes to provide structural support in extremely high shock
and vibration applications. CCAs may be configured for various
platform and application requirements including but not limited
to 3U or 6U VME, VPX, IEEE 1101.2 and VITA 30.1 applications.
Code keys are attached to the PCB or CCA to mitigate the
risk of inadvertent PCB insertion into an incorrect slot within the
Mechanical PCB Hardware and Retainer Applications
Multiple retainer types are available to meet the unique needs
of every application.
In many industrial settings, continuous vibration poses a unique
challenge to PCBs. Retainers are used to keep circuit boards in
complete alignment and firmly positioned in their card slot. In ad-
Table of Contents for the Digital Edition of Electronics Protection - Spring 2015
Predictive Modeling: The Next Frontier in Data Center Condition Maintenance
Don't Forget the Batteries
Military Aircraft Power
Pumped Two Phase Cooling Solutions for Challenging Thermal Management Applications
Identifying the Ideal Mechanical PCB Hardware for Electronic Systems
Bridging the Technology Gap: The Importance of Cyber and Physical Security within the Data Center
Waterproof Mobile Device Protection without Compromising Acoustic Quality
Electronics Protection - Spring 2015